This NIH SBIR project intends to develop three product lines of near infrared (NIR) bio-medical labeling reagents based on semiconductor nanocrystals (NIR NanoLabels), including conventional core/shell nanocrystals, type-II core/shell nanocrystals, and quantum well type-ll nanocrystals. NIR fluorescence labels are of great advantages because body tissues are uniquely transparent in this wavelength widow and organic dyes are generally not ideal NIR labeling. The NIR NanoLabels to be developed by this program will be bio-accessible, bio-compatible, photo-stable, chemically stable, bright, and of large absorption cross-section and excitation window. The nanocrystals to be used will include both quantum dot and quantum well structures. The specific aims of this project are 1) produce InAs based core/shell nanocrystals by a one-pot approach and Successive-lonic-Layer-Adsorption-and-Reaction (SILAR). Although InAs/lnP/CdS core/shell nanocrystals are the main target, two other types of potential candidates, InAs/lnP and InAs/CdS core/shell nanocrystals will also be studied. 2). produce CdSe/CdTe or CdTe/CdSe type-ll core/shell nanocrystals by SILAR and develop standard procedures. 3). produce CdS/CdSe/CdTe or CdS/CdTe/CdSe quantum well type-ll nanocrystals by SILAR and develop standard procedures. 4). develop dendron-nanocrystals and box-nanocrystals by chemical modification of these nanocrystals.